Galls are modified, invariably symmetrical, naturally developing plant structures that arise because of messages from certain specialist insects, mostly from the Thysanoptera, Hemiptera, Diptera, and Hymenoptera, and in a lesser frequency from the Lepidoptera and Coleoptera. Several species of the Eriophyoidea (Acari) induce galls and wherever appropriate, we have considered examples from the Eriophyoidea as well, generically referred under the term “insects”. The insects live within them, deriving nourishment and shelter. When these insects attack plant tissues, osmotic-change–related stress increases, thus stimulating alterations in gas exchange and subcellular metabolic functions. The osmotic stress alters the electrical properties of the plant-cell plasma membranes and impacts on indole-acetic acid synthesis and activity, which, in turn, affects the H⁺-transport. Insect action stimulates parts of host-cell wall to break down and the degenerated wall materials in the cytoplasm act as elicitors. In such contexts the susceptible plants use flexible strategies to mitigate stress, which generally manifest as galls. Inherited traits also play a role in providing specific shapes to the gall, which is coordinated by the innate correlating morphogenetic factors that operate normally in the plant. The gall-inducing Diptera (Cecidomyiidae), Hemiptera (Sternorrhyncha), and Hymenoptera (Cynipidae) induce galls of highly defined and exquisite shapes. Almost all of these insects are known for their specificity to plants. The gall-inducing insects, unlike many of their free-living relatives, discriminate between plants and choose from them. Selection of a particular plant by a gall-inducing insect is not a matter of chance, given that the insect encounters varied plant taxa in the natural environment. The gall-inducing insects preferentially feed on specific plant organs, or parts of these, and on specific plant species. One recent explanation is that the gall-inducing insects prefer certain plants or parts of those plants, because they need the lipidic materials, e.g., sterols, available in those plant parts, which the insects utilize for building hormones critically necessary for their metamorphosis. Because of the sedentary nature of the juvenile stages of the inducing insect, the gravid females endowed with specialized sensory structures play a key role in selecting the site precisely for oviposition and thus for the progeny. Although a majority of gall-inducing insects are restricted to specific plant taxa, some of them, as we presently know, are indicated to be capable of inducing galls on plant species closely related to their mostpreferred hosts, thus demonstrating some level of oligophagy. A few species of Asphondyliina and Schizomyiina (Cecidomyiidae) are presently indicated as polyphagous. Clearly demonstrated host shifts and adaptive radiation in some of the European and North-American gall-inducing Tephritidae populations explain the evolution of sympatric host races, more because of changes either in the preference of feeding and/or oviposition sites or by acquiring “new” physiological adaptations to new plants or through assortative mating. Differences in the temporally regulated flowering and leafing phenologies in the susceptible plants possibly play a role in isolating gall-inducing insect populations, which enable divergence and diversification via genetic drift. The general understanding, as of now, is that host shifts and radiation in gall-inducing insects are more complex than what is known in their non-gallinducing allies. Such a complexity is attributed to intricate relationships of gall-inducing insects with plants and the dispersal of gall-inducing insects through different biogeographical realms, mainly influenced by the abundance and variety of plant species. The gall-inducing insects, as a highly evolved group, present a stunning diversity, yet share the distinct capacity to redirect developmental programs of plants by generating galls. Propagation of the progeny manifests more prominently in the hemipteroids and Acari, whereas this behavior is not that prominent in the more-derived gall-inducing groups, such as the Cecidomyiidae and Cynipidae, wherein the gall as a facility is better used for the nutrition and development of the immature stages of the inducing insect taxon. The gallinducing insects are easy to monitor because of the distinct presence of galls, offering an advantage in extending in investigations about the eco-physiology of several other economically important, non-gall-inducing insects. The gall-inducing insects could be termed as ecosystem engineers in the sense that they manipulate plant architecture to create novel habitats. Their impacts on plants will continue to bear scrutiny, especially in regions where gallinducing insects have been introduced and released from their natural enemies, thus potently threatening various other plants, including the economically relevant ones.

The total solar eclipse of 21 August 2017 traversed ~5000 km from coast to coast of North America. In its 90-min span, sunlight dropped by three orders of magnitude and temperature by 10–15°C. To investigate impacts of these changes on bee (Hymenoptera: Apoidea) pollinators, we monitored their flights acoustically in natural habitats of Pacific Coast, Rocky Mountain, and Midwest regions. Temperature changes during the eclipse had little impact on bee activity. Most of the explained variation (R²) in buzzing rate was attributable to changes in light intensity. Bees ceased flying during complete darkness at totality, but flight activity was unaffected by dim light in partial phases before and after totality. Flights of bees during partial phases of the eclipse lasted longer than flights made under full sun, showing that behavioral plasticity matched bee flight properties to changes in light intensity during the eclipse. Efforts of citizen scientists, including hundreds of school children, contributed to the scope and educational impact of this study.

The effects of plant species richness on the function and stability of ecosystems have been an area of focus in recent decades. Arthropod community is one of the most important components in agroecosystems and can provide multiple ecosystem services, including biocontrol and pollination. In particular, species composition and biocontrol function can be sensitive to changes in plant species richness. Here, we designed 50 plots with five levels of plant species richness to examine arthropod distribution and composition over 4 yr. Arthropod richness was found to be positively correlated with plant species richness. High plant species richness can enhance the temporal stability of the arthropod community but can also lead to a decline in the population stability of some species. The species richness and biomass of environmentally friendly insects (EFI), such as honeybees, ants and flies, were found to be positively correlated with those of the natural enemies. As such, high levels of EFI could sustain food web robustness by serving as alternative prey/hosts for natural enemies. The mediation of EFI in the interaction between crops and pests has implications for successful biocontrol practices using natural enemies. Planting diverse plant species with a certain level of spatial turnover could benefit the biocontrol function of natural enemies and safeguard multiple ecosystem services.

Throughout its range in Africa, Papilio dardanus Brown, 1776 (Lepidoptera: Papilionidae) displays femalelimited mimicry of multiple model species, and the absence of hind wing tails is an important component of their mimetic convergence. Nonmimetic P. dardanus females have a narrow, disjunct distribution (Ethiopia, Madagascar, Comoros), and resemble males in color and by possessing hind wing tails. We used elliptical Fourier analysis to investigate whether mimetic P. dardanus female forms converged on the wing shape of their unpalatable models in the tribes Acraeini and Danaini (Lepidoptera: Nymphalidae). Models varied in forewing and hind wing shapes, and separated in shape space according to phylogenetic affinities. Forewing and hind wing shapes of mimics did not closely match those of models. Nonetheless, we found that mimetic P. dardanus female hind wings differed from conspecific males that had their tails photographically removed to allow standardized comparisons. Four nonmimetic Papilio Linnaeus, 1758 (Lepidoptera: Papilionidae) species did not show significant wing shape dimorphism between sexes, supporting the idea that in P. dardanus females, the evolution of mimicry led to changes in hind wing shape beyond the loss of tails.

The Philippines is a biodiversity hotspot and is home to thousands of endemic species, including at least two understudied bumble bee species: Bombus flavescens Smith, 1952 and Bombus irisanensis Cockerell, 1910. Since the 1990s, there have been virtually no studies published on the biology, ecology, and taxonomy of Philippine bumble bees—evidence of the dearth of basic entomological investigations on these important insects. In this preliminary study, our objective is to briefly summarize the geographic distribution of bumble bee habitat suitability (HS) in the Philippines across protected and unprotected areas. Maximum entropy species distribution models (SDMs) of B. flavescens and B. irisanensis were constructed using 19 unique occurrence records and 11 bioclimatic variables to estimate HS in the Philippines. Our SDMs estimated that minimum HS for B. flavescens and B. irisanensis covers ~28,066 and ~24,603 km² of the 114 protected land parcels in the Philippines, respectively. Across unprotected areas, our SDMs estimated that minimum HS for B. flavescens and B. irisanensis covers ~146,063 and ~156,674 km², respectively. As predicted, high-elevation habitats have the highest HS relative to low-elevation habitats (r = 0.61, P = 0.003). While our SDMs predicts an extensive distribution of both species across both protected and unprotected areas, it is important to note that nearly 80% of the Philippines is deforested. Our study identifies high-elevation protected areas as places where bumble bees may still thrive, and survey effort should be prioritized to these places to determine the status of Philippine bumble bees.

The rosemary grasshopper, Schistocerca ceratiola Hubbell and Walker (Orthoptera: Acrididae), is unusual because it is one of only two known species of monophagous grasshoppers in North America and is nocturnal. S. ceratiola is a specialist herbivore of Florida rosemary, Ceratiola ericoides Michuax. Ceratiolin, the most abundant secondary metabolite in the plant, represents the only known example of a photoactivated allelopathic compound. Ceratiolin decomposes in sunlight to yield hydrocinnamic acid and other undescribed breakdown products. Due to the monophagous behavior, ceratiolin is ingested every time S. ceratiola feeds. Coupled with the nocturnal behavior of S. ceratiola, a connection to the photolytic properties of ceratiolin warrants investigation. We hypothesize that the breakdown products of ceratiolin represent potentially noxious compounds and S. ceratiola may exhibit nocturnal feeding behavior to avoid ingesting ceratiolin in sunlight where it readily decomposes. To our knowledge, this is the first chemical ecology study of a specialist herbivore of C. ericoides and a possible connection between the nocturnal behavior of S. ceratiola and ceratiolin. Qualitative analysis by liquid chromatography and tandem mass spectrometry was performed on the regurgitant, hemolymph, and frass of S. ceratiola to determine whether ceratiolin is confined to the gut or if it transports to the hemocoel. We also analyzed samples for the presence of hydrocinnamic acid to determine whether ceratiolin decomposes after it has been ingested. We detected ceratiolin in the regurgitant and frass. We did not detect hydrocinnamic acid in the regurgitant, hemolymph, or frass. Our results indicate that ceratiolin is confined to the grasshopper gut. We discuss more than one opportunity for future chemical ecology studies in this system.